The invention relates to an apparatus for electrically connecting at least one electrical component to a first and second busbar, which busbars have a different potential to one another during electrical operation. The invention further relates to a converter which comprises the apparatus.
In converters of relatively high output, for electrical energy transmission in a DC network, in general, busbars with a large cross-section and a large surface area are used which enable an electrical connection from electrical or electronic components to the DC supply network. For reasons of environmental conditions, however, tight limits are usually imposed on a generous spatial arrangement of the busbars and the electrical components. Busbars lying directly opposite one another with respectively different potentials, in DC systems a positive potential opposite a negative potential, are often arranged at a small separation from one another.
The smaller the separation between busbars with different potentials in operation is selected to be, the greater is the danger that, due to insufficiently dimensioned air gaps or leakage paths between the two busbars, a short-circuit occurs in the form of a flashover. The air gap in the electrical context generally denotes the shortest distance between two electrical conductors (busbars) of different potential and the leakage path in the electrical context usually denotes the shortest distance along the surface of a solid insulating means between two electrical conductors (busbars).
In known manner, such flashovers can be prevented by the introduction of an electrical insulation between the two busbars. The selection of the insulation medium and the dimensioning of this electrical insulation usually takes place on the basis of relevant norms and standards taking account of the type and size of the voltage occurring in operation, as well as the structural arrangement of the busbars arranged opposite one another. For busbars with a small spacing from one another, for example, electrically insulating films are used which electrically insulate the busbars from one another.
The electrical connection of an electrical component to two busbars arranged opposite one another can take place, for example, by means of two terminal studs which are part of the electrical component. These terminal studs require a connecting opening of the first busbar and a through opening of the opposite second busbar and a further connecting opening of the second busbar and a further through opening of the opposite first busbar. A first terminal stud of the electrical component can be fed through the second busbar and connected mechanically and electrically to the connecting opening of the first busbar, and a second terminal stud of the electrical component can be fed through the further through opening of the first busbar and connected mechanically and electrically to the further connecting opening of the second busbar.
In order to prevent a flashover between, for example, the first terminal stud connected to the connecting opening of the first busbar and the passage opening of the second busbar, the passage opening of the second busbar is often selected to be excessively large, in contrast to the connecting opening of the first busbar, so that the electrically insulating film can achieve a sufficient insulating effect.
In particular, the passage openings selected, as a precaution, to be large lessen the conductivity of the busbar at these sites by reducing the conductive material and, associated therewith, with a consequent increase in the electrical resistance in the busbars. Electrical losses on the busbars which can have negative effects, in particular, on the efficiency, the availability and/or the operating life of the busbars and of the electrical components connected to the busbars are intrinsic to the system under these conditions and can only be kept within acceptable economic and technical limits with generous or over-dimensioned design of the busbars, the electrical connections and possibly also the electrical components attached to the busbars.